Method of combating weeds



United States Patent '0 METHOD OF COMBATING WEEDS Ralph P. Neighbors,Olathe, and Lee V. Phillips, Overland Park, Kans., assignors to GulfResearch & Development Company, Pittsburgh, Pa., a corporation ofDelaware 1 No Drawing. Filed May 29, 1967, Ser. No. 642,174 Int. Cl.A01n 9/20; C07c 131/00 US. Cl. 71-121 19 Claims ABSTRACT OF THEDISCLOSURE Weeds in crops such as oats, corn (maize), wheat and grainsorghum are combated by applying to the locus of the weeds effectiveamounts of certain O-substituted amidoximes, particularlyO-2,3,6-trichlorobenzoyl and -3, 6-dichloro-2-methoxy-benzoyl esters ofcyclopropanecarboxamidoxime and isobutyramidoxime.

SUMMARY OF INVENTION oats, corn, wheat and grain sorghum to obtain bothpreemergent and post-emergent control of a variety of undesirablevegetation, including both broadleaf species and grasses such ascrabgrass, brome and millet.

Briefly, my method comprises applying to the locus of the weeds aherbicidally effective amount of an O-subsituted carboxamidoximerepresented by the structural formula XC=NOCY N 'Hz g in which X isorganic and is selected from the group consisting of methyl, alkyl,cycloalkyl, chloromethyl, chloroalkyl, phenyl, chlorophenyl,chlorophenoxymethyl and methoxyphenyl and Y is chloro-substitutedorganic, selected from the group consisting of substituted methyl,phenoxymethyl phenyl and phenylmethyl structures which have at least twochloro substituents. Some of the free acids which correspond to theO-acyl substituents in the structural formula also possess phyotoxicproperties, but

are deficient as to both the high activity and selectivity of theamidoxime esters of the present invention.

DETAILED DESCRIPTION (A) PREPARATION OF THE WEED AGENTS f CONTROLPreparation of isobutyramidoxime Reaction:

wmponoN 112N011 onozono uon 3,547,621 Patented Dec. 15, 1970 Materialsg. (1.81 moles, isobutyronitrile V 136 g. (1.96 mole) hydroxylaminehydrochloride 135.5 g. (0.98 mole) potassium carbonate Procedure:

To a stirred solution of 136 g. (1.96 moles) of hydroxylaminehydrochloride in 250 ml. of water was added slowly a solution of 135.5g. (0.98 mole) of potassium carbonate in ml. of water. A solution of 125g. (1.81 moles) of isobutyronitrile in 1 liter of ethanol Was added andthe mixture was stirred at room temperature for 30 min., then heated atreflux temperature for 4 hrs. The reaction mixture was cooled to roomtemperature and the solvent was removed under reduced pressure to leavea solid residue. This material was recrystallized from a henzene-hexanesolvent mixture to give 87 g. of isobutyramidoximine, M.P. 602 C.

This procedure may be employed with only slight modification to make allof the amidoximes, as the necessary nitriles are either availablecommercially or are easily prepared by known methods. The conversion ofamidoximes to esters is illustrated below.

Preparation of O-(2-methoxy-3,6-dichlorobenzoy1)isobutyramidoximeReaction:

Cl 0 I ll (C2H5)3N (CHs)zCH-(|J=NOH 010- NHi I 01 (CHshCH (IJ=N o o--{NE: I

Materials:

10.2 g. (0.1 mole) isobutyramidoxime 24.0 g. (0.1 mole)2-methoxy-3,6-dichlorobenzoyl chlo ride 10.1 g. (0.1 mole) triethylamineProcedure:

To a stirred solution of 10.2 g. (0.1 mole) of isobutyramidoxime, 10.1g. (0.1 mole) of triethylamine and 250 ml. of acetone was added dropwise24.0 g. (0.1 mole) of 2-methoxy-3,6-dichlorobenzoyl chloride while thetemperature was kept below 30 C. After addition had been completed, themixture was stirred at room temperature for 2 hrs., then the acetone wasremoved under reduced pressure. The residue was dissolved in ethylacetate, extracted with water, dried over magnesium sulfate andevaporated to dryness under reduced pressure. The residue wasrecrystallized from benzene-hexane to give 19.3 g. of O-(2-methoxy 3,6dichlorobenzoyl)isobutyramidoxime, M.P. 92-94 C.

Analysis.calcd for C H Cl N O (percent): C, 47.23; H, 4.62; N, 9.18.Found (percent): C, 47.39; H, 4.51; N, 9.15.

(B) USE OF O-SUBSTITUTED AMIDOXIMES AS HERBICIDES Specific compoundswere employed as weed control agents on a variety of representativeplant species under carefully controlled conditions so as to evaluateboth activity and selectivity of herbicidal action, according to thefollowing procedures:

What is claimed is:

1. The method of combating weeds which comprises applying to the locusof the weeds a herbicidially effective amount of an O-substitutedcarboxamidoxime represented by the structural formula I IIIB (I) inwhich X is organic and is selected from the group consisting of, alkyland chloro-substituted alkyl substituents having from 1 to 5 carbonatoms, cyclopropyl, phenyl, chlorophenyl, chlorophenoxymethyl andmethoxyphenyl and Y is chloro-substituted organic, selected from thegroup consisting of substituted methyl, phenoxymethyl, phenyl andphenylmethyl structures which have at least two chloro substituentsattached thereto.

2. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,4-dichlorophenoxyacetyl)-acetamidoxime.

3. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,4-dichlorophenoxyacetyl)-chloroacetamidoxime.

4. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally efiective amount ofO-(dichloroacetyl)-2,4-dichlorophenoxyacetamidoxime.

5. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,4-dichlorophenylacetyl)-2,4-dich1orophenoxyacetamidoxime.

6. The method of combating Weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,3,6-trichlorobenzoyl)-cyclopropanecarboXamidoXime.

7. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally efiective amount ofO-(2,3,6-trichlorobenzoy1)-4-methoxybenzamidoxime.

8. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally efiective amount ofO-(2,3,6-trichlorobenzoyl)-isobutyramidoxime.

9. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,3,6-trichlorobenzoyl)-4-chlorobenzamidoxime.

10. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,3,6-trichlorophenylacetyl -cyc1opropane carboxamidoxime.

11. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally efiective amount ofO-(2,5-dichloro-6-methoxybenzoyl)-cyclopropanecarboxamidoxime.

12. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,3,6-trichlorophenylacetyl)-benzarnidoxme.

13. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,3,6-trichlorobenzoyl)-benzamidoxime.

14. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount of O-2,3,6-trichlorobenzoyl -acetamidoxime.

15. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount of 0- (2,3,fi-trichlorobenzoyl -butyramidoxime.

16. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,5-dichloro-6-methoxybenzoyl)-isobutyramidoxime.

17. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,3,6-trich1orophenylacetyl)-isobutyramidoxime.

18. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount of 0- (2,3,6-trichlorobenzoyl -isovaleramidoxime.

19. The method of combating weeds which comprises applying to the locusof the weeds a herbicidally effective amount ofO-(2,5-dichloro-6-methoxybenzoyl)-isovaleramidoxime.

References Cited UNITED STATES PATENTS 3,483,231 12/1969 Marcus et a1,71121X 3,492,333 1/1970 Dickore et al. 71 121x FOREIGN PATENTS 824,53412/1959 Great Britain 71-121 JAMES O. THOMAS, JR., Primary Examiner US.Cl. X.R. 260566

